NXP Semiconductors
QN908x
DK User Guide
QN908x-DK
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© NXP B.V. 2017. All rights reserved.
User guide
Rev. 1.0
— June 2017
10 of 28
3. DK board application function
3.1 CMSIS-DAP interface
The QN908x DK V1.2 board offers the JTAG/SWD interface either to the on-board or
off-board QN908x targets. It also provides the USB-to-UART interface for QN908x.
3.1.1 CMSIS-DAP to on-board QN908x
When programing or debugging a QN908x device using the CMSIS-DAP interface, JP1
and JP2 must be configured according to
Table 3
.
Table 3.
ISP mode jumper setting
JP1
Open, CMSIS-DAP target is on-board QN9080
JP2
Short pin 1, 2, QN908x power enable
When downloading firmware into the QN908x with the ISP mode, enable the UART path
and set the chip mode pin to ground. The jumper setting is shown in
Table 4
.
Table 4.
ISP mode jumper setting
JP8
Short, UART path enable
JP15
Short, ISP mode enable
The ISP download operation flow is shown in
Fig 11
.
Fig 11. ISP download operation flow
After the ISP download operation, move the jumper cap on JP15 away and leave JP15
open. Then, the QN908x chip can go into the normal mode normally.
3.1.2 CMSIS-DAP to off-board target
When using the QN908x DK board to program or debug off-board targets by the
JTAG/SWD interface, JP1 and JP2 must be configured according to
Table 5
.
Table 5.
ISP mode jumper setting
JP1
Short, CMSIS-DAP target is off-board target
JP2
Short pin 2,3, 3 V power disable on JTAG/SWD connector
3.2 Current consumption test
The QN908x DK board provides two ways to measure the QN908x chip current
consumption. One way is to measure the current by the on-board precise resistor used
for the I-to-V conversion. The small voltage signal is amplified by the operation amplifier
and fed to the ADC. Then, it can be calculated by LPC4322 and shown in the
MCUXpresso IDE. Another way is to measure the current by an external ammeter on
jumper JP14.
UART
Enable
Short ISP
Jumper
ISP
Loading
Press QN908x
RST
Button
